1. Field of the Invention
This invention relates to a method of making a top toothed endless power transmission belt construction formed mainly of polymeric material as well as to a belt construction made by such method.
2. Prior Art Statement
It is known in the art of making a top toothed endless power transmission belt construction formed mainly of polymeric material to dispose the material in substantially cylindrical form on a substantially cylindrical drum-like support member, dispose a substantially cylindrical toothed member about the disposed material, and compress one of the members toward the other of the members with the pressure of pressurized steam to form top teeth in the material and cure the thus formed material into a top toothed belt construction.
For example, see the following U.S. patent:
(1) U.S. Pat. No. 4,106,966--Brooks
It had been found that it is necessary to eliminate the adverse effect of the expanded gas created in the heated polymeric material being formed by the method set forth in the above U.S. Pat. No. 4,106,966 in order to permit the outer collapsible toothed matrix thereof to fully form the top teeth during the compressing of the toothed matrix toward the inner support member by utilizing at least one layer of fabric or flocking material between the toothed matrix and the polymeric material to absorb such expanding gas and provide an escape path therefor.
It is also known in the belt making art wherein a relatively long endless belt construction is being formed with teeth in the top surface thereof by serially compressing and heating straight segments of the belt construction between forming flat plates, the top flat plate after initially compressing into the particular belt segment to partially form top teeth therein is backed off therefrom before that belt segment is cured in order to permit the expanded gas in the heated polymeric material of that segment to escape. Thereafter the top plate is again compressed against the respective belt segment to further form the teeth thereof and final cure that segment of the belt construction before the next segment of the belt construction is indexed between the flat forming plates.